IRyS is good at Splatoon and that's it. She is a decent enough gamer, but does not play FPS competetively enough outside of Splatoon to be anywhere near Towa or Botan.
Where does it say the participation is optional, actually? I ran the page through MTL and it didn't say anything about participcation. It actually is a concern if they expected the girls to participate given their current workload, but also, it wouldn't make sense if it were forced.
Either way, not with just this, but Cover is really putting their hands in too many baskets, imo. I genuinely don't see a point in putting resources into hosting their own e-sports events rather than continuing to let the talents join others.